Induction system of internal-combustion engines



Oct. 21 1924.

H. R. RICARDO INDUCTION SYSTEM OF INTERNAL COMBUSTION ENGINES Filed Jan. 12 1924 F/GTZ.

ders 1 and 4 and. those of Patented Oct. 21, 1924.

. UNITED STATES 1,512,311 PATENT OFFICE.

nanny RALPH RICARDO, on LoNnoN, ENGLAND.

INDUCTION SYSTEM. OF INTERNAL-COMBUSTION ENGINES.

Application filed January 12, 1924. Serial No. 685,786.

To all whom it may concern:

Be it known that I, HARRY RALPH RICARDO, subject-of the King of England, and residing at London, in England, have invented certain new and useful Improvements in the Induction Systems of Internal- Combustion Engines, of which the following is a specification.

This invention relates to the induction systems of internal combustion engines and more particularly to the induction systems of four cylinder fourstroke internal combustion engines of the type in which the combustible mixture is supplied to all four cylinders by a single carburettor and in which the inlet ports of all four cylinders are independent of one another. I

The object of this invention is to provide an induction system for such engines which will give increased uniformity in the strength of the mixture and the weight of the c arge supplied to the several cylinders as compared with that given by known induction systems and which shall give this improved result without recourse to excessive velocities or to excessive heating.

According to this invention two mparate and non-communicating induction conduits are provided, each of which extends between the induction ports of two of the cylinders whose inlet valves are actuated so that there are equal time intervals between the successive openings of these induction conduits communicate with a sinle carburettor by means of two pipes ranching from above the carburettor, each of these branch pipes opening substantially] at right angles into'the' centre of the lengt of one of the induction conduits. Preferably the two induction conduits extend as directly as is practicable between the inlet ports with which they communicate and the branch pipes from the carburettor are conveniently at an acute angle to each other.

This invention is-particularly applicable to verticalfour-cylinder engines having cranksin the same plane and at 180 to each other. If, as is usual I with such engines, the firing order .of the cylinders is 1-3- -4-'2,' then'the inlet spectively connected by separate. induction conduits '1n the manner escribed above,

these conduits being conveniently horizontal and communicating with a single carburettor preferably by means of vertical conduits.

ports, and these .ports of cylin-. 2 and 3 are re-' Thus if cylinder N o. 1 performs its induction stroke andthe closing of its inlet valve sets up oscillations in the horizontal induction conduit connecting it with cylinder No. 4, these oscillations do not have any appreciable effect on the combustible mixture in the vertical conduit communicating with the carburettor since the mixture can oscillate freely in the horizontal conduit between cylinders 1 and 4. Still less can these oscillations have any effect on the mixtu're in the horizontal induction pipe connecting cylinders 2 and 3, so that when cylinder N o.

3 performs its induction stroke the mixture drawn in is unafi'ected by oscillations set up ll Iy the closing of the inlet valve of cylinder Further, b the time the induction period of cylinder 0. 4 begins such oscillations have to a large extent been damped out, since although cylinder No. 4 draws its combustible mixture from the same induction pipe as cylinder No. 1, there is an appreciable time interval between the closing of the inlet port' of cylinder No. 1 and the time when that of cylinder No. 4 opens. Similarly as no two cylinders draw consecutively from the same induction pipe, each -cylinder receives a charge unaffected by the closing of the inlet port of the preceding cylinder.

This invention may be carried out in va-' rious ways but. one arrangement according to this invention is illustrated somewhat diagrammatically in the accompanying drawings in which-'- Figure 1 is a horizontal section of an en-.

gine having an inductionsystem according to this invention.

Figure 2 is a transverse 'the same engine.

-Figure 3 is a side elevation with the crank case broken away showing the arrangement of the cranks. A i y The en e shown has four cylinders A, B, C, D fiving separate inlet ports indicated at A, B C, D. The cranks L, M, N, O of the en ine are in the same plane those of cache the pairs A, B and C, D being at 180 to one another as shown in Figure 3, and the arrangement is such that the firing order of the V -B. The inlet ports in each of thepairs A, D, and B, C, are respectively connected b two entirely separate and substantially honvertical section of cylinders is A, C, D, Y

zontal induction pipesE and F which communicate with the carburettor G by means of two substantiall vertical pipes H and J opening respectively into the induction pipes E and F at right angles thereto and at or about the centres of their lengths. The two pipes H and J merge into a single pipe In just above the carburettor, the angle between the pipes being as illustrated preferably acute.

The operation of the engine is as follows.

Assume that the firing order of the engine is A, C. D, B, for example. Cylinder A performs its induction stroke and on the inlet valve closing the gas column proceeding along the horizontal portion of the manifold E which connects A and D is arrested, and rebounds along this manifold towards cylinder D. As there is every opvVG ' ment described above may be modifiedin} accordance with the type of engine to which the invention is applied. c

While especially applicable to four-cylin ortunity for the rebounding gas to oscillate freely between cylinders A and D, there 1s no inducement for the oscillating gas to set up any appreciable disturbance in. the vertical branch H from the carburettor which leads into it at right angles. With the firing order under consideration, cylinder C will have commenced its induction stroke before cylinder A has completed its induc tion stroke, but owing to the fact that cylinders B and, C are fed by the manifold F independent from the manifold E which feeds cylinders A and D, the oscillation of the column of gas in the manifold E will not affect, for the reasons already stated, the induction stroke of cylinder C. At the completion of the suction stroke of the cyl-.

inder C the rebound of .the gas column caused by the shutting of the inlet valve-of cylinder C will setup an oscillation of the gas column in the manifold F connecting cylinders B and C, and this oscillation can proceed freely-as was the case'when describing the suction stroke of cylinder A as the two manifolds are entirely favourable to the free."

oscillation of columns of gas within them in their horizontal portions without having any inducement or facility for/settin up disturbance in the vertical branches and J which lead into them.

It will be seenthat with this arrangement no two cylinders with cranks at 180 draw successively from any one conduit, so that after any one cylinder is filled the flow of gas in that conduit ceases, whereas when. one conduit feeds two cylinders with cranks at 180 as in known constructions, the secf 0nd cylinder receives a richer mixture and 1greater weight of charge owingf'togthe.

ocity setup by the first, for theadvanrg tage dueto the kinetic energy of the column is reaped only by the second cylinder.

It is to be understood that the arrangeij neiaeii der four-cycle engines it may be utilized with engines having more than four cylinders.

What I claim as my invention and desire to secure by Letters Patent is 1. In an internal combustion engine operating on the four-stroke cycle and having four cylinders and four separate inlet ports, the combination of two separate and noncommunicating induction conduits each of which extends between the induction ports ofv two cylinders whose inletvalves are actuated so that there are equal time intervals between the successive openings of these ports, a carburettor, and two pipes branch ing from above the carburettor each branch pipe opening substantially at right angles into the centre of the length of an induction conduit.

2. In an internal combustion engine operating on the four-stroke cycle and having four or more cylinders, a plurality of induction conduits each of which connects the intake ports of a plurality of cylinders whose suction strokes do not overlap, a carbureter, and means for conducting gaseous fuel from the carbureter to each of said conduits, said means. comprising a conduit having one inlet anda plurality of outlet ports, said conduit being branched remote from said outlet ports which commuicate respectively with said induction conduits.

3. In an internalcombustion engine operating on the four-stroke cycle and having four or more-cylinders, a plurality of induction conduits each of which connects the intake ports of a plurality of cylinders whose suction strokes do not overlap, a carbureter, and means for conducting gaseous fuel from the carbureter to each of said conduits, said means comprising a branched conduit having one inlet and a plurality of outlet ports opening respectively into said induction conduits, said conduit freely communicating through its outlet ports with the induction conduits respectively, at points midway of the length of each.

4. In an internal combustion engine op erating on the four-stroke cycle and having four cylinders and four separate'inlet ports, the combination of two separate and noncommunicating induction conduits each of which extends between the induction ports of two cylinders whose inlet valves are actuated so that the suction strokes of the cylinders, don'ot overlap, a carbureter, and a conduit leading from the carbureter to the induction conduits said conduit having two branches and each branch opening sub- 1 stantially at right angles into an induction f'fconduit midway of its length.

15:5. lln aninternal combustion en ine op- .eratingon the four-stroke cycle an having four cylinders and four separate inlet ports, the combination of two separate and nonlid llii

communicating induction conduits each of bureter to the induction conduits said. conwhich extends between the induction ports duit having two branches and each branch of two cylinders whose inlet valves are so opening substantially at right angles into 1 actuated that there is an appreciable inan induction conduit midway of its length.

5 terval between the end of oneinduction In testimony whereof I have signed my stroke and the beginning of the other, a carname to this s ecification. bureter, and a conduit leading from the car- HA RY RALPH RICARDO. 

